We propose a new interpretation of Hubble law. Waves are observed in the observer space-time. It defines the observer proper time T. Space-time is composed of three spatial dimensions and three temporal parameters: proper-time s of the observed object, proper time T of the observer and integration time t (currently considered as relative time). Time origin is the birth of the universe. So, universe is stable; it can be seen as the comobile space of expansion theory. When changing space-time from the source to the observer, waves are seen cooling; this explains the redshift effect. The distance is defined as the product of the delay time with the local speed of light of the observer. The mistake between t and T can explain why universe is viewed as not only in expansion but also in acceleration whereas we think it is stable.